Subject: grep 2.20 perl-regexp: invalid UTF-8 byte sequence in input

From: Paul Eggert <[email-masked]>
Date: Thu, 11 Sep 2014 20:40:35 -0700

This appears to be the same as Bug#18266:

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=18266

which means it's fixed in the master version and the fix should appear 
in the next release.